The project is safe and open:

The patch installer, the patch itself, and the server have fully open source code.

The project is based on a system of alternative (but not pirated, license only) servers from TLeonardUK (https://github.com/TLeonardUK/ds3os).

The archive with the current source code of the project can be downloaded here: DSO Project source.

Curious players can, without much effort (but with some skill), decompile the current installer and launcher downloaded directly from the site!
Stack:

• Installer: launcher files and the script-installer packed in a self-extracting 7zip archive (SFX).
• Installer itself: written in Ahk, very easy to decompile.
• Launcher: C# .NET 6.0 Desktop, also easy to decompile.